RE: query performance - getting started
Date: Fri, 8 Apr 2011 08:19:58 -0400
Message-ID: <C95D75DD2E01DD4D81124D104D317ACA16155AD3BA_at_JAXMSG01.crowley.com>
Very good, I remember that now from the good 'ol days. Thx for the doc Ids.
Joel Patterson
Database Administrator
904 727-2546
From: Chitale, Hemant Krishnarao [mailto:Hemant.Chitale_at_sc.com] Sent: Friday, April 08, 2011 2:06 AM
To: Patterson, Joel
Cc: oracle-l_at_freelists.org
Subject: RE: query performance - getting started
You can check to see if the MV refresh really does a TRUNCATE. If you can query and see data while the Refresh is running, then a DELETE-INSERT is being done.
To revert to the 9i behaviour of TRUNCATE-INSERT , set ATOMIC_REFRESH to FALSE in your DBMS_MVIEW.REFRESH call.
(See OracleSupport article Complete Refresh Read Consistency Behavior During Refresh and Complete Refresh Performance as Influenced by the ATOMIC_REFRESH Refresh Parameter [ID 553464.1]
)
You can also define the MV to use Parallel Query in the COMPLETE Refresh's.
(See OracleSupport article How to Refresh a Materialized View in Parallel [ID 577870.1] )
Hemant K Chitale
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Joel.Patterson_at_crowley.com Sent: Thursday, April 07, 2011 8:51 PM
To: Joel.Patterson_at_crowley.com; oracle-l_at_freelists.org Cc: kylelf_at_gmail.com
Subject: RE: query performance - getting started
Query performance continued.
We have a very complicated Materialized view, and a view that utilizes the MV. We cannot use Fast refresh - a complete refresh is necessary. The app can decide when the view is refreshed, and can execute dbms_refresh when necessary.
Essentially all records are truncated, and the view is rebuilt as part of the complete refresh. So, is this just as easy, efficient as any other method such as Temp tables, Truncating a permanent table and re-inserting, or other?
Moving forward,
JP
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